Addition of ATRA to the Maintenance Protocol Did Not Improve Disease-Free Survival: Results of the Russian APL Trial.

Russian Leukemia study group is presenting the final analysis of the APL-06.01. randomized clinical trial. The aim of the study was to identify the efficacy of ATRA substitution of each other chemotherapy course while the 2-yrs maintenance after three induction/ consolidation 7+3 with daunorubicin dose of 180 mg/m2 per course and ATRA for 30 days while the first induction. The patients were randomized for two types of maintenance - (I type) rotation of 5-days ARA-C (100 mg/m2 bid) combined with daunorubicin (45 mg/m2 for 2 days, till the total dose of 650 mg/m2) or 6-MP (50mg/m2 p.o.5 days) or CHP (800 mg/m2 i.v.1 day) or (II type) rotation of the same courses of chemotherapy with 5-days 45 mg/m2 ATRA course. The II type of maintenance treatment contained twice less chemotherapy. The intervals between courses were 4 weeks From July, 2001 till January, 2006 114 APL patients from 26 centers were enrolled in the study. In 95% of pts APL was confirmed by cytogenetics or PCR. 102 patients were included in the analysis. CR rate was 85%, ED rate -15%, 4-yrs OS -68,3%, DFS - 77,4%, CCR - 89,5%. Suvival analysis according to randomization did not demonstrate statistical differences, but showed a trend (p=0,06) towards better DFS and CCR in patients maintened with chemotherapy only: 85,2% and 94,3% (I type) and 77,7% and 85,6% (II type). In the multivariant analysis only one factor was defined as statistically significant - the number of the patients randomized by the participating centers. OS and DFS were much higher in the centers randomized 6 and more patients comparing with less than 6 patients: 82,9%and 90,7% vs 48,8% and 63%, respectively (0,003). 1. So we can suggest that maintenance with ATRA alternating with chemotherapy is less effective than chemotherapy only. Whether addition not substitution of ATRA to chemotherapy maintenance will change the results will be checked in the next study.2. The experince of the centers in APL treatment is a cruicial point for survival.